What is your definition of a two QB system? Tebow threw 33 passes (2.5 per game) and had 89 rushing attempts (6.3 per game) for the year. That's probably 10-12 plays per game with a future Heisman winner and three-time Heisman finalist. I'd say that's a pretty extreme example. Now if you're saying TA will be of the same caliber, I guess I can live with that.Florida won the NC in 2006 with a two QB system. It can be done. Osborne rotated Frazier and Berringer in 95 Orange Bowl. Granted their were extenuating circumstances that led to that happening.
If the starter is playing well. Then by all means keep him in the game if the defense is not letting the team getting seperation. However, if the offense is stagnant perhaps a new signal caller can give the team a spark.